Carburizing container



March 19, 1929. w. J. MERTEN CARBURIZING CONTAINER Filed May l1, 1927 INVENTOR Ml//am J Neffe/1.

ATTORNEY,

Patented Mar. 19, 1929.

PATENTyoFFIcn g WLLIAM iT, MERTEN, OF PTTSBRGH, PENNSYLVANIA,I1SSGNOR TO WIEIS'IING-` HOUSE ELECTRIC & MANUFACTURNG COMPANY, A CORPORATION OF PENNSYL- VANIA.

Appication filed May 11,v

My invention relates to the process of carburization andV particularly toa self sealing carburizing container for holding the carburixing material and the nietal objects vto be carburized.

in the carburizingg; process well known tothe art the material to be carburized and the carburizer are placed in a inetal container and covered byametal cover or lid. It is necessary that the seal between cover and con tainer bepracticaily air-tight in order to prevent reaction with the oxygen of the air la l I cover 1s preferably of the dimensions of the thus forming Fe() and CO2 and delaying the carburizing reaction. v

Hitherto it has been the practice to'seal the joint `between the cont ner and cover by luting the joint with clay or other refractory material. Such luting clays influence the ceinentation process unfavorably because they contain oxide carrying n'iaterials which react with and eonsiune the carbon of the carburizing material. Furthermore such a clay lutin is` likely to crack during the carburizing process thus providing channels by rneans of which the carburizing gases may escape or the air inay enter. y

Therefore, among the objects of iny invention to j irovide a container constructed entirely of instal and having a inetal seal. or joint of a kind such that the ceinentation process will not be affected by the material used in making the oint.

Another object of iny invention is to pro vide container which will be practically airtight and thus improve carburization.

A further object of my invention is to provide a container liaving a strong durable joint which is not readily subject to'wear,

whereby the saine cover may be used repeatedly without repair or replacement of parts. Other advantages will. become apparent in the following description of iny device in which `like numerals indicate like parts throughout the several figures: j

Figure 1 is a sectional end view of my container. Y,

Fig. 2 is a sectional side view of vthe container.

F ig. 3 is a top View ofthe copper gasket used in my device; and r Fig. l is an enlarged sectional view of my sealing device.

The container or boX 1 inay be a cast-iron box having its upper edge turned into a i the art.

.portion of the flange.

l CABB'URIZING CONTAINER. I'

1927. Serial N0.'190,554.

U-shaped flange 2 on either two or three sides thereof. Therr inside portion 3 ofthe U-shaped flange provides means for gripping or engaging the cover and gasket. The portion 4 ofl the U-shaped flange preferably extends over the opening inthe boX in order to pro- Vide a better sealbetween the cover and the,

container. However,A if preferred the box may be made of a special steel alloy and cut, shaped or welded'in a manner well known to A sheet iron cover 5 is provided and this outside walls of the container so that'it will extend over the walls and engage the upper portion 4L oi' theYU-shaped fiange of the container.

A copper gasket 6, rectangular in shape is so proportioned that it rests on the seat 7 provided by the inner portion of the U-shaped flange. The inside dimensions are preferably such that the gasket projects into the inside of the container. f

The gasket G andcover 5 are slid into place on the box from the unflanged end of the box. The thickness of the gasket and cover are such that-when. they are in placeon the boil' a close` fitissecured at ordinary rooin teinperature. The copper gasket engages the box so that the edge of the gasket just reaches the beginning ofthe circular portion Soit the turn of the flange. If' desired thecover or the f gasket or both may be slightly wedge shaped and a close fit will incre easily be secured.

in the process ofcarburizing, the container is heated from rooin temperature to a teinperature of about 900 centigrade. The coefiicient of expansion of copper is greater than the coefficient of expansion of iron. Therefore the combined thickness of the copper gasket and the iron cover will Ahave increased more than the inside measurement of the U- shaped fiange between the seat and the upper (Dotted lines Fig. 4.) The horizontal dimension of the gasket also increases and consequently will be forced' against the circular portion -of the fiange. Therefore, a practically air-tight seal or joint will be formed whenV the box is at the carburizing temperature.

Because the joint is air-tight no air can reach the inside of the container and interfere With the carburizing process. Furthermore, a pressure slightly above atmospheric will be maintained Within the container and result in accelerating, deepening and making more uniform the carbnrization of the parts.

Copper is chemically inert to the carburizing gas, and therefore does not interfere With or in any Way affect carburization. 'lhe iron cover' will. become carburized but such action does not effect its utility nor eect the carburizing process.

After the carburizing process has been completed and the temperature of the container brought to room temperature the gasket, cover and box will have of course re` gained their former dimensions and the cover may then be easily removed.

The copper will of course have become ductile but its utility will not be affeeted'since carburizing gases have little or no eii'eot on copper. rlherefore, the gasket may be used repeatedly until it has become so worn that it vvill no longer be effectiveas a seal.

lWhen several containers are to be used the inside dimensions of the ll-shaped flanges i2 may be made smaller in successive containers so that when a gasket becomes too thin for one container it may be used on a container having a decreased inside dimension of the lU-shaped flange. Another means for taking up Wear vis to insert Wedges at points 9 be tween the upper portion l of the flange 2 and the cover 5.

lt is apparent that modifications of my de vice will suggest themselves to those skilled in the art. For example, the cover may be provided with the ilil-shaped flange and the box with the engaging flange. Although l have described a specific modification of my device l do not Wish to be limited to the modification shown since other modications of my device may be made Without departing from the spirit and scope of my invention as defined in the appended claims.

l claim as my invention:

l. A carburizing container' comprising a box member having an opening in one side thereof, a cover member, a plurality of Ushaped flanges extending over the opening, said flanges being disposed to form a seat for said cover member, and a metal gasket of' material having a greater coefficient of expanmesma sion than the material of the flanges disposed between said cover member and said flanges.

2. A carburizing container comprising a box member having an opening in the upper side thereof, a cover member, a U-shaped flange member on three sides of said opening so disposed a to form a seat for said cover member, and a metal gasket having a higher coefficient of expansion than the material of the flange disposed between said cover mein-l ber and a portion of said U-shaped flange for y the purpose-of sealing the cover to the flange when heated.

3. A ca-rburizing container comprising a. bo); member having an opening in one side thereof, a cover for said opening, a flange on the bo:\r member for engaOing said cover and a gasket of a material having a higher coeflicientof expansion than the material of the flange disposed between said cover and said flange whereby said cover Will engage said flange by reason of the expansion of the materials of said members When they are heated.

l. A carburizing container comprising a' b member having an opening in one side thereof, a cover for said opening, a Hangs on the bos; member for engaging said cover andv a gasket disposed between said cover and said y ,said gasket having a greater coefficient of expansion `than said cover andl flange, whereby said ga ket and cover will be tightened in said flange when the earburizing container is heated.

5. A container comprising a box made of a mataial having a positive coefficient of expansirm when heated, a cover member and a gasket having a greater positive coefficient of expansion, a lll-shaped flange on said box for engaging said cover and gasket, forforming a seal with said cover when they are heated.

6. A. metal rwal comprising a itl-shaped flange consisti g of metal having a positive coefficient of expansion, a seat in said flange, a cover member for engaging' the seat and a gasket consistipg` of metal having' a greater positive coefficient of expansion than said firstV named metal, said gasket being mounted onl aid seat so that it will be tightened between said flange and cover when heated.

ln testimony whereof, lA have hereunto subscribed my naine this 2nd day of May, 1927.

Wllililnhl J. MERTEN. 

